The invention relates to connectors for signal conductors such as optical communication fibers.
Known fiber optic connectors enable two optical fibers to be connected end-to-end, or allow the connection of a fiber to a device, such as optical sources (lasers and LED's), optical receivers (PIN or APD diodes), etc. Fiber optic connectors are generally designed to minimize losses in the connection.
Several quick-fit standard connectors are known for use with optical fiber. An "FC" connector is a circular metal connector, where the male-to-female mechanical parts thread together. An "ST" connector is much like a BNC connector. The mechanical parts of an ST connector include a male metal cylindrical bayonet part that inserts into a cylindrical female part. The male part has a small stud that protrudes radially, that fits into a J-shaped channel in the wall of the female part. Once the stud reaches the bottom point of the J, a tension spring holds it there. An "SC" connector is rectangular, generally made of plastic, and the two mating components are mechanically conjoined by a snap-fit tongue. There are other standards for quick-fit optical connectors, as well.
In these three example standards, the terminal centimeter or so of the fiber is held in a ceramic ferrule, about 2.5 mm in diameter. (Other standards use other diameters for the ferrules, for instance 1.5 mm.) A ceramic split sleeve assists the mechanical parts of the connectors to hold two ferrules in an opposed coaxial relationship, so that an optical signal from one fiber falls on the end of the other.
Optical fiber based transmission systems have historically been designed to maximize optical power transmission to achieve high-speed, long-distance communications. More recently, optical fiber based systems are deployed in relatively short-distance applications and within other complex optical systems that require that the optical power be managed. Optical attenuators regulate the absolute power level of light traveling within any given path of an optical transmission system. In short distance applications, excessive power is attenuated to maintain the strength of an optical signal within a certain range, to avoid receiver saturation. More advanced optical systems, such as those employing fiber amplifiers and wavelength division multiplexing (WDM) or dense wavelength division multiplexing (DWDM), require careful optical power management in order to optimize system performance.